Numerous attempts have been made to formulate laundry detergent compositions which provide the good cleaning performance expected of them and which also have good textile softening and anti-static properties. Attempts have been made to incorporate cationic textile softeners in anionic surfactant-based built detergent compositions employing various means of overcoming the natural antagonism between the anionic and cationic surfactants. For instance, U.S. Pat. No. 3,936,537, Baskerville et al., issued Feb. 3, 1976, discloses detergent compositions comprising organic surfactant, builders, and, in particulate form (10 to 500 microns), a quaternary ammonium softener combined with a poorly water-soluble dispersion inhibitor which inhibits premature dispersion of the cationic in the wash liquor. Even in these compositions some compromise between cleaning and softening effectiveness has to be accepted. Another approach to provide detergent compositions with softening ability has been to employ nonionic surfactants (instead of anionic surfactants) with cationic softeners. Compositions of this type have been described in, for example, German Pat. No. 1,220,956, assigned to Henkel, issued Apr. 4, 1964; and in U.S. Pat. No. 3,607,763, Salmen et al., issued Sept. 21, 1971. However, the detergency benefits of nonionic surfactants are inferior to those of anionic surfactants.
Other laundry detergent compositions have employed tertiary amines along with anionic surfactants to act as textile softeners. British Pat. No. 1,514,276, Kengon, published June 14, 1978, employs certain tertiary amines with two long chain alkyl or alkenyl groups and one short chain alkyl group. These amines are useful as fabric softeners in detergent compositions when their isoelectric point is such that they are present as a dispersion of negatively charged droplets in the normally alkaline wash liquor, and in a more cationic form at the lower pH of a rinse liquor, and so become substantive to fabrics. The use of such amines, among others, in detergent compositions has also been previously disclosed in British Pat. No. 1,286,054, assigned to Colgate-Palmolive, published Aug. 16, 1972, British Pat. No. 1,514,276, assigned to Unilever, published June 14, 1978, and in U.S. Pat. No. 4,375,416, Crisp et al., issued Mar. 1, 1983.
Another approach to provide anionic detergent compositions with textile softening ability has been the use of smectite-type clays, as described in U.S. Pat. No. 4,062,647, Storm et al., issued Dec. 13, 1977. These compositions, although they clean well, require large contents of clay for effective softening. The use of clay together with a water-insoluble cationic compound in an electrically conductive metal salt as a softening composition adapted for use with anionic, nonionic, zwitterionic and amphoteric surfactants has been described in British Pat. No. 1,483,627, assigned to Proctor & Gamble, published Aug. 24, 1977.
British patent application Nos. 1,077,103 and 1,077,104, assigned to Bayer, published July 26, 1967, disclose amine-anionic surfactant ion-pair complexes useful as antistatic agents. These complexes are applied directly to the fabric from an aqueous carrier. There is no suggestion in either of these references that such complexes could be added to detergent compositions to impart fabric care benefits through-the-wash. In fact, such complexes are delivered in solubilized form and therefore could not be delivered through-the-wash.
Fatty acid-amine ion-pair complexes in granular detergents are disclosed in European patent application No. 133,804, Burckett-St. Laurent et al., published June 3, 1985. While this complex delivers fabric conditioning benefits, the amine-anionic surfactant ion-pair complexes of the present invention provide superior antistatic performance.
More recently, in European patent application, No. 87202159.7 filed Nov. 6, 1987, amine-anionic compound ion-pair complex particles having an average particle diameter of from about 10 microns to about 300 microns were disclosed. These particles provide excellent through-the-wash softening without significantly impairing cleaning performance. Furthermore, European patent application No. 87202159.7 further discloses that ion-pair particles which are made from lower chain length amines impart improved processing characteristics and improved chemical stability in liquid detergents. Still, further improvements in processing characteristics of the particles and, with respect to liquid detergent formulations, improved chemical stability of the ion-pair particles in detergent bases to provide longer shelf-life at low cost, are desirable.
It is an object of the present invention to provide a conditioning agent, fabric care compositions, and detergent compositions, in both liquid and granular formulations, which can be used through-the-wash (i.e., can be added to the wash prior to initiation of the rinse cycle) and provide excellent fabric conditioning benefits without significantly impairing the cleaning performance of detergent or other cleaning compositions, and further, which can be easily processed using conventional equipment for forming particles, e.g., prilling equipment. In particular, ease of consistently forming the conditioning agent in the form of essentially spherical particles within a desired size range is one desirable processing improvement. Another desirable processing improvement is ease of handling, especially with respect to incorporation of the particles into granular compositions. (As used above, the term "fabric care composition" refers to compositions containing at least one conditioning agent useful for fabric care, but not containing a significant amount of fabric cleaning ingredients. The term "detergent composition", as used above refers to compositions containing at least one conditioning agent useful for fabric care and also containing one or more fabric cleaning ingredients.)
It is yet another object of this invention to provide liquid detergent compositions having a fabric conditioner which provides excellent through-the-wash fabric conditioning without significantly impairing cleaning performance and which also has improved chemical stability in liquid detergent compositions.
It is still another object of this invention to provide fabric conditioning particles for liquid detergent compositions which provide excellent through-the-wash fabric conditioning without significantly impairing cleaning performance, and which also are characterized by both improved processing and improved stability in liquid detergent compositions.